In this study, a nano-scale palladium thin film etch process for few layer sulfide synthesis was investigated. Firstly, an illumination of laser beam of wavelength 1064nm was applied on Pd film surface at room temperature with a controlled humidity and reaction pressure (1 atm). By changing the illumination powers and energy density, the modification of surface bonding before and after illumination were examined. Secondly, the illuminated Pd films were treated by evaporated formic acid steam at 80℃. Through the AFM and XPS inspection in film thickness and binding conditions, the Pd film was etched and the etches thickness were proportional to the applied laser powers. The minimum and maximum etch depth of 0.5 nm and 6.5 nm per cycle were achieved when the applied power were 12W and 27W, respectively. A reliable and cyclable etch process had also been demonstrated.
As to the sulfide synthesis, a single zone tube furnace was used for metal film sulfidation. The sulfur and the etched Pd film were put at opposite direction of heating center for sulfur concentration tuning and process optimization. By changing the shown in the heating temperature, and the sample position, the optimal Pd-S condition Raman spectrum of was obtained. The layered Pd-S structure synthesis would be well controlled in such a two-step sulfurization process.